JP2012240294A - Inkjet printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably convey a printing paper to prevent the contact with an inkjet head while preventing adhesion of an ink mist to a paper press roller pressing the printing paper to be conveyed.SOLUTION: An inkjet printing device includes a paper conveying unit 133 for conveying the printing paper W to be conveyed, an inkjet head unit 31 for discharging the ink disposed in a line shape, a suction fan 131 for sucking the printing paper W to be conveyed to a conveying road surface side, and the paper pressing roller 139 for pressing the printing paper W to the conveying road. The paper conveying unit 133 has a through-hole 142 passing through the conveying road, and an air chamber 143 which includes opening from the position of the through-hole 142 to the position right under the paper pressing roller 139 at the downstream side in the conveying direction of the printing paper W on the surface of the inkjet head unit 31 side around the through-hole 142 respectively.

Description

  The present invention relates to an inkjet printing apparatus provided with a plurality of line-type inkjet units arranged for each ink color.

  In general, an ink jet printing apparatus including a plurality of ink jet heads that eject ink in a direction orthogonal to a transport direction of a printing paper transported on a transport path surface is well known.

  In such an ink jet printing apparatus, a belt platen that conveys the print paper while being sucked by a suction fan is provided below the ink jet head, and the print paper conveyed by the belt platen does not contact the ink jet head. In many cases, a paper pressing roller for pressing the printing paper is provided on the belt platen side.

  An ink jet printing apparatus provided with a fan for sucking generated mist is also well known in order to prevent ink mist discharged from the ink jet head from adhering to the printing paper.

  For example, Patent Document 1 proposes an ink jet recording apparatus provided with a fan that sucks mist of ink ejected from an ink jet head from the downstream side in the conveyance direction of printing paper.

  Patent Document 2 proposes a liquid ejection device that sucks ink mist by an exhaust fan provided on the upper part of each inkjet head.

JP 2006-110987 A JP 2009-220499 A

  However, in the technique described in Patent Document 1, ink mist is sucked from the downstream side in the transport direction. Therefore, when this technique is applied to an ink jet printing apparatus including a sheet pressing roller, the mist adheres to the sheet pressing roller. There was a problem that the adhered ink contaminates the printing paper.

  Further, in the technique described in Patent Document 2, since the ink mist is sucked by the exhaust fan provided at the top of each inkjet head, it is difficult to transport the printing paper while sucking the printing paper to the belt platen side. .

  The present invention has been made in view of the above problems, and appropriately prevents printing paper from being brought into contact with an inkjet head while preventing ink mist from adhering to a paper pressing means that presses the conveyed printing paper. It is an object of the present invention to provide an ink jet printing apparatus for transport.

  In order to achieve the above object, a first feature of the ink jet printing apparatus according to the present invention is that a suction conveyance unit that sucks and conveys printing paper, and a suction conveyance unit that is provided above the suction conveyance unit, An inkjet head that discharges a plurality of lines of ink arranged in a line in a direction perpendicular to the conveyance direction, and is provided above the suction conveyance unit and upstream of the inkjet head in the conveyance direction of the printing paper. A sheet pressing unit that suppresses the lifting of the printing sheet, and the suction conveyance unit includes a first through hole that is provided through the upper and lower sides, a periphery of the first through hole, and the inkjet head side. An air chamber that is opened from the position of the first through hole to a position directly below the sheet pressing means on the downstream side in the conveyance direction of the printing sheet. And a second through hole penetrating up and down, a belt moving on the platen portion in the transport direction, a lower portion of the platen portion, the first through hole, and the air And a suction fan that sucks air above the belt through the second through-hole and sucks the printing paper onto the belt.

  A second feature of the ink jet printing apparatus according to the present invention is that the platen portion includes a plurality of the first through holes, and a plurality of the air chambers corresponding to the periphery of each of the plurality of first through holes. The plurality of air chambers have substantially the same opening area.

  According to the first feature of the ink jet printing apparatus according to the present invention, the air chamber is provided to be opened from the position of the through hole to a position directly below the sheet pressing means on the downstream side in the conveyance direction of the printing sheet. Thus, it is possible to appropriately convey the printing paper so as not to contact the ink jet head while preventing the ink mist from adhering to the paper pressing means for pressing the printing paper to be conveyed.

  According to the second feature of the ink jet printing apparatus according to the present invention, since the plurality of air chambers have substantially the same opening area, the printing paper can be uniformly sucked toward the conveying means.

It is a block diagram which shows the structure of the inkjet printing apparatus which is Example 1 of this invention. FIG. 2 is a perspective view illustrating a paper transport unit provided in the ink jet printing apparatus according to the first embodiment of the present invention with a part cut away. 1 is a plan view of a paper transport unit included in an inkjet printing apparatus that is Embodiment 1 of the present invention. FIG. It is the enlarged plan view which expanded a part of plastic template with which the inkjet printing apparatus which is Example 1 of this invention is provided. * Plastic template It is a side view of the paper conveyance unit with which the inkjet printing apparatus which is Example 1 of this invention is provided. It is the enlarged plan view which expanded a part of plastic template with which the inkjet printing apparatus which is Example 2 of this invention is provided. It is the enlarged plan view which expanded a part of plastic template with which the inkjet printing apparatus which is Example 3 of this invention is provided.

  Embodiments of the present invention will be described with reference to the drawings.

  In the first embodiment of the present invention, a line type image formation is performed in which a plurality of inkjet heads each having a large number of nozzles are provided, and black or color ink is ejected from each inkjet head and printing is performed on a printing sheet line by line. The apparatus will be described as an example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Overall configuration of inkjet printing apparatus>
The configuration of the inkjet printing apparatus 1 that is Embodiment 1 of the present invention will be described in detail.

  FIG. 1 is a configuration diagram illustrating a configuration of an inkjet printing apparatus 1 that is Embodiment 1 of the present invention.

  As shown in FIG. 1, the inkjet printing apparatus 1 includes a side paper feed unit 10, an internal paper feed unit 20, a printing unit 30, a paper discharge unit 40, and a reversing unit 50.

  The side paper feeding unit 10 includes a paper feeding table 11 on which the printing paper W is stacked, and a primary paper feeding unit 12 that conveys only the uppermost printing paper W from the paper feeding table 11 onto the paper feeding conveyance path FR. And a secondary paper feeding unit 14 for carrying the printing paper W conveyed by the primary paper feeding unit 12 onto the circulation conveyance path CR.

  The internal paper feed unit 20 includes a paper feed tray 21a on which the print papers W are stacked, and a primary paper feed unit 22a that transports only the uppermost print paper W from the paper feed tray 21a onto the paper feed transport path FR. The printing paper W is laminated, the primary paper supply unit 22b that conveys only the uppermost printing paper W from the paper feeding base 21b onto the paper feeding conveyance path FR, and the printing paper W. Sheet feeding table 21c, a primary sheet feeding unit 22c that conveys only the uppermost printing sheet W from the sheet feeding table 21c onto the sheet feeding conveyance path FR, and a sheet feeding table 21d on which the printing sheets W are stacked. And a primary paper feed section 22d for transporting only the uppermost printing paper W from the paper feed tray 21d onto the paper feed transport path FR.

  In this way, the printing paper W is conveyed from the side paper feeding unit 10 and the internal paper feeding unit 20 to the secondary paper feeding unit 14, and further, the printing paper W is also conveyed from the reversing unit 50 described later.

  Therefore, in front of the secondary paper feeding unit 14 in the transport direction, the transport path of the fed printing paper W and the path through which the paper on which one side is printed are circulated and merged are merged A point exists. Based on this merging point, the path on the paper feed mechanism side is referred to as a paper feed conveyance path FR, and the other path is referred to as a circulation conveyance path CR.

  The printing unit 30 includes a paper transport unit 133 that transports the print paper W on the circulation transport path CR, and an ink jet head unit 31 that is provided above the paper transport unit 133 and incorporates a plurality of ink jet heads.

  The paper transport unit 133 includes an annular platen belt 132, and the printing paper W fed by the secondary paper feed unit 14 is placed on the platen belt 132 by a suction fan 131 (described later) installed in the platen belt 132. The ink is sucked by the ink and is printed on the printing paper W by the ink ejected from the inkjet head unit 31 while being transported on the transport path at a predetermined transport speed.

  The printing paper W printed by the printing unit 30 is conveyed on the circulation conveyance path CR in the housing by a conveyance roller or the like disposed on the circulation conveyance path CR. A switching mechanism 43 is provided on the circulation conveyance path CR to switch between guiding the printing paper W conveyed on the circulation conveyance path CR to the paper discharge unit 40 or recirculating it on the circulation conveyance path CR. Yes.

  The switching mechanism 43 switches the printing paper W in order to guide it to one of a paper discharge unit 40 and a reversing unit 50 described later.

  The paper discharge unit 40 includes a tray-shaped paper discharge table 41 protruding from the casing of the inkjet printing apparatus 1 and a pair of paper discharge rollers 42 that guide the print paper W to the paper discharge table 41. Then, the printing paper W guided to the paper discharge unit 40 by the switching mechanism 43 is conveyed to the paper discharge table 41 by the paper discharge roller 42, and is stacked on the paper discharge table 41 with the printing surface facing down.

  The reversing unit 50 reverses the printing paper W, and the reversing unit 51 conveys the printing paper W from the circulation conveyance path CR to the reversing table 51 or conveys the printing paper W from the reversing table 51 onto the circulation conveyance path CR. And a roller 52.

  The printing paper W guided to the reversing unit 50 by the switching mechanism 43 is transported from the circulation transport path CR to the reversing table 51 by the reversing roller 52, and is transported from the reversing table 51 to the circulation transport path CR after a predetermined time. Thus, the front and back are reversed with respect to the circulation conveyance path CR. The printing paper W whose front and back are reversed is conveyed toward the printing unit 30 on the circulation conveyance path CR by a plurality of rollers such as a conveyance roller 53 provided on the circulation conveyance path CR.

  FIG. 2 is a perspective view in which the paper transport unit 133 provided in the inkjet printing apparatus 1 according to the first embodiment of the present invention is partially cut away.

  As shown in FIG. 2, the paper transport unit 133 includes a platen belt 132 that transports the printing paper W, a plate template 134 that supports the platen belt 132, and an air volume average that makes the suction pressure constant on the lower surface of the plate template 134. A plate portion 135 and a chamber portion 136 that surrounds an intake passage from a suction fan 131 (described later) to a belt hole provided on the platen belt 132 in an airtight state are provided.

  The platen belt 132 is an endless belt member having a large number of belt holes 141 for adsorbing the printing paper W at regular intervals. The platen belt 132 is supported by a platen template 134 and is wound around a pair of driving rollers 137 and driven rollers 138 arranged orthogonal to the conveyance direction of the printing paper W, and is circulated in the conveyance direction. The upper surface of 134 is slid.

  The plastic template 134 is a plate-like plate member having a large number of through-holes 142 that are penetrated at places where the belt holes 141 pass.

  Below the plastic template 134, a suction fan 131, which is a suction means for generating a negative pressure for adsorbing the printing paper W on the plastic template 134 through the through hole 142 and the belt hole 141, is provided.

  A plurality of suction fans 131 are provided on the lower surface of the air volume average plate 135 in the inkjet printing apparatus 1.

  The chamber portion 136 is a partition member that surrounds the intake path from the suction fan 131 to the belt hole 141 in an airtight state. The chamber portion 136 is disposed in each of the suction fans 131 and has an inclined surface that is inclined downward from the upstream end portion of the platen belt 132.

  FIG. 3 is a plan view of the paper transport unit 133 provided in the ink jet printing apparatus 1 according to the first embodiment of the present invention.

  As shown in FIG. 3, an ink jet head unit 31 is provided above the paper transport unit 133.

  The ink jet head unit 31 has a plurality of ink jet head rows 32 to 39 arranged in a line shape, here in a staggered manner, in a direction orthogonal to the transport direction of the printing paper W.

  The inkjet head row 32 includes inkjet heads 321 to 323 that discharge cyan (C) ink, and the inkjet head row 33 includes inkjet heads 331 to 333 that discharge cyan (C) ink. The inkjet heads 321 to 323 and 331 to 333 are arranged in a staggered manner. For example, the inkjet head 331 is disposed so as to partially overlap the inkjet heads 321 and 322 with respect to the conveyance direction of the printing paper W, and the inkjet head 332 is disposed so as to partially overlap the inkjet heads 322 and 323. The inkjet head 333 is arranged so as to partially overlap the inkjet head 323. Thereby, the inkjet head rows 32 to 33 can print cyan (C) ink in a direction perpendicular to the transport direction of the printing paper W without a gap.

  Similarly to the inkjet head rows 32 to 33, the inkjet head rows 34 to 35, the inkjet head rows 36 to 37, and the inkjet head rows 38 to 39 are respectively black (K), magenta (M), and yellow (Y). An ink jet head that ejects ink onto the printing paper W and is arranged in a staggered pattern.

  Under the inkjet head unit 31 arranged in this way, the printing paper W is conveyed while being attracted to the upper surface of the platen belt 132 of the paper conveying unit 133.

  Further, on the platen belt 132, a sheet pressing roller on the upstream side in the printing sheet W conveyance direction of each inkjet head row in the conveyance direction of the printing sheet W so that the conveyed printing sheet W does not contact the inkjet head unit 31. 139 is provided.

  The sheet pressing roller 139 is disposed in contact with the platen belt 132 and presses the printing sheet W toward the platen belt 132 by being driven to rotate following the rotation of the platen belt 132.

  FIG. 4 is an enlarged plan view in which a part of the plastic template 134 included in the inkjet printing apparatus 1 that is Embodiment 1 of the present invention is enlarged. Here, the plastic template 134 in the vicinity of the inkjet head 352 that is one of the inkjet head rows 35 is shown and described, but the same applies to other inkjet heads included in the inkjet head unit 31.

  As shown in FIG. 4, the plastic template 134 of the paper transport unit 133 has a plurality of through holes 142 that penetrate the plastic template 134 in the vertical direction.

  The through hole 142 is provided between the upstream side paper pressing roller 139 and the downstream side paper pressing roller 139 so that the printing paper W conveyed on the plastic template 134 is uniformly sucked on the platen belt 132. Arranged in a staggered pattern. For example, as illustrated in FIG. 4, the through hole 142 a on the upstream side paper pressing roller 139 d and the through hole 142 b on the downstream side paper pressing roller 139 e side alternate with respect to the conveyance direction of the printing paper W. It is provided as follows.

  An air chamber 143 is provided around the through hole 142 so as to correspond to each through hole 142.

  In the example shown in FIG. 4, an air chamber 143a is provided around the through hole 142a on the inkjet head 352 side. The air chamber 143a is provided in the conveyance direction of the printing paper W so as to open from a position in front of the inkjet head 352 to a position directly below the paper pressing roller 139e.

  An air chamber 143b is provided around the through hole 142b with respect to the conveyance direction of the printing paper W. The air chamber 143b is provided in the conveyance direction of the printing paper W so as to open from a position directly below the inkjet head 352 to a position beyond the paper pressing roller 139e.

  As described above, in the inkjet printing apparatus 1 that is Embodiment 1 of the present invention, at least the air chambers 143 around the through holes 142 and on the surface on the inkjet head side are at least in the transport direction of the printing paper W. An opening is provided from the position of the through hole 142 to a position directly below the sheet pressing roller 139 on the downstream side in the printing sheet W direction.

  FIG. 5 is a side view of the paper transport unit 133 provided in the inkjet printing apparatus 1 according to the first embodiment of the present invention.

  As shown in FIG. 5, the plastic template 134 has a through-hole 142a and an ink-jet head 352 around the through-hole 142a on the side of the ink-jet head 352 in the conveyance direction of the printing paper W, immediately below the paper pressing roller 139e. An air chamber 143a provided so as to be open is provided corresponding to the through hole 142a.

  Here, “directly below” is a position where the distance from the plastic template 134 is the shortest. In the sheet pressing roller 139e having a cylindrical shape, the position of the lowest point of the roller is the position immediately below. Further, in an inkjet head having a rectangular parallelepiped, any position on the lower surface, which is an ink ejection surface, is a position immediately below.

  When the platen belt 132 moves on the platen template 134 in the conveyance direction, the printing paper W sucked on the platen belt 132 is also conveyed.

  When the position in the transport direction of the printing paper W exceeds just below the inkjet head 352, the airflow AF generated by the suction of the suction fan 131 wraps around the leading edge of the printing paper W as shown in FIG. It passes through 132 belt holes 141. Here, the airflow AF may include a mist of ink ejected from the inkjet head 352.

  Also at this time, since the air chamber 143a is provided so as to be opened just below the sheet pressing roller 139e, the airflow AF that has passed through the belt hole 141 passes through the air chamber 143a and the through hole 142a, and the air volume average A flow that passes through the plate 135 is formed.

  Further, when the printing paper W is transported and the leading edge of the printing paper W exceeds the paper pressing roller 139e, there is no gap between the printing paper W and the paper pressing roller 139e, so that the airflow AF is directly below the inkjet head 352. The mist discharged from the inkjet head 352 stays in the vicinity of the inkjet head 352. As a result, the mist is not sucked in the direction of the paper pressing roller 139e and attached to the paper pressing roller 139e, so that the printing paper W can be prevented from being contaminated by the mist.

  As described above, according to the inkjet printing apparatus 1 that is Embodiment 1 of the present invention, the plurality of through holes 142 that penetrate the plastic template 134 and the periphery of the through holes 142 on the inkjet head unit 31 side are provided. And a plastic template 134 provided with an air chamber 143 that is opened from at least the position of the through hole 142 in the conveyance direction of the printing paper W to a position directly below the paper pressing roller 139 on the downstream side in the printing paper W direction. The printing paper W can be appropriately conveyed so as not to contact the inkjet head unit 31 while preventing the ink mist from adhering to the paper pressing roller 139.

  In the first embodiment of the present invention, the air chamber 143a opened from the position in front of the inkjet head 352 to the position just below the sheet pressing roller 139e in the conveyance direction of the printing paper W, and the inkjet recording medium in the conveyance direction of the printing paper W. The inkjet printing apparatus 1 including the plastic template 134 provided with the air chamber 143b that is opened from a position directly below the head 352 to a position beyond the sheet pressing roller 139e has been described as an example. The opening areas may be the same.

  FIG. 6 is an enlarged plan view in which a part of the plastic template 134 included in the inkjet printing apparatus 1 according to the second embodiment of the present invention is enlarged.

  As shown in FIG. 6, the plastic template 134 of the paper transport unit 133 has a plurality of through holes 142 that penetrate the plastic template 134.

  The through-hole 142 penetrates on the upstream side of the sheet pressing roller 139d with respect to the conveyance direction of the printing paper W in the same manner as the through-hole 142 of the plastic template 134 provided in the inkjet printing apparatus 1 according to the first embodiment of the present invention. The holes 142a and the through holes 142b on the downstream side paper pressing roller 139e side are provided alternately, that is, in a staggered manner.

  The air is provided on the side of the inkjet head unit 31 around the through-hole 142a and opened from the position in front of the inkjet head 352 to the position directly below the sheet pressing roller 139e in the conveyance direction of the printing sheet W. It is provided on the inkjet head unit 31 side around the chamber 143a and the through-hole 142b, and is opened from the position immediately below the sheet pressing roller 139d to the position beyond the sheet pressing roller 139e in the conveyance direction of the printing sheet W. Air chamber 143c. As shown in FIG. 6, the air chamber 143a and the air chamber 143c have the same opening length in the transport direction, that is, the air chamber 143a and the air chamber 143c have the same opening area. ing.

  Accordingly, the flow velocities in the air chamber 143a and the air chamber 143c are substantially equal, so the suction force for sucking the print paper W is also substantially equal, and the print paper W can be sucked uniformly toward the platen belt 132.

  As described above, according to the inkjet printing apparatus 1 that is Embodiment 2 of the present invention, the air chamber 143a and the air chamber 143c are provided to have the same opening area. Therefore, Embodiment 1 of the present invention. In addition to the effects of the inkjet printing apparatus 1 as described above, the printing paper W transported on the plastic template 134 can be more uniformly sucked on the platen belt 132 in the direction orthogonal to the transporting direction of the printing paper W. Therefore, there is an effect that the printing paper W is not easily wrinkled.

  Note that the opening areas of the air chamber 143a and the air chamber 143c are not necessarily the same, and a deviation in the size of the opening area is allowed to some extent within a range in which the flow velocity hardly changes.

  In the first embodiment of the present invention, the air chamber 143a opened from the position in front of the inkjet head 352 to the position just below the sheet pressing roller 139e in the conveyance direction of the printing paper W, and the inkjet recording medium in the conveyance direction of the printing paper W. The inkjet printing apparatus 1 including the plastic template 134 provided with the air chamber 143b opened from a position directly below the head 352 to a position exceeding the sheet pressing roller 139e has been described as an example. The positions of the air chambers in the direction may all be the same.

  FIG. 7 is an enlarged plan view in which a part of the plastic template 134 included in the inkjet printing apparatus 1 according to the third embodiment of the present invention is enlarged.

  As shown in FIG. 7, the plastic template 134 of the paper transport unit 133 has a plurality of through holes 142 that penetrate the plastic template 134.

  The through-hole 142 penetrates on the upstream side of the sheet pressing roller 139d with respect to the conveyance direction of the printing paper W in the same manner as the through-hole 142 of the plastic template 134 provided in the inkjet printing apparatus 1 according to the first embodiment of the present invention. The holes 142a and the through holes 142b on the downstream side paper pressing roller 139e side are provided alternately, that is, in a staggered manner.

  In addition, the ink jet head unit 31 is provided around the through hole 142a in the conveyance direction of the printing paper W so as to be opened from a position directly below the paper pressing roller 139d to a position directly below the paper pressing roller 139e. An air chamber 143e is provided.

  As shown in FIG. 7, the air chamber 143e is provided so that the position and the opening area in the transport direction are the same.

  Thereby, since the flow velocities in all the air chambers 143e are substantially equal, the suction force for sucking the printing paper W is also substantially equal, and the printing paper W can be sucked uniformly toward the platen belt 132.

  As described above, according to the inkjet printing apparatus 1 that is Embodiment 3 of the present invention, the air chambers 143e are provided so that the positions and the opening areas in the transport direction are the same. In addition to the effect of the inkjet printing apparatus 1 as Example 1, the printing paper W conveyed on the plastic template 134 is more uniformly sucked on the platen belt 132 in the direction orthogonal to the conveyance direction of the printing paper W. Therefore, there is an effect that the printing paper W is not easily wrinkled.

DESCRIPTION OF SYMBOLS 1 ... Inkjet printing apparatus 10 ... Side paper feeding part 20 ... Internal paper feeding part 30 ... Printing part 31 ... Inkjet head unit 32-39 ... Inkjet head row 40 ... Paper discharge part 50 ... Reversing part 131 ... Suction fan (suction fan)
132 ... Platen belt (suction conveyance means)
133 ... Paper transport unit 134 ... Plastic template (platen section)
135 ... Airflow average plate 136 ... Chamber part 137 ... Drive roller 138 ... Driven roller 139, 139d, 139e ... Paper pressing roller (paper pressing means)
141 ... Belt hole 142 ... Through hole 143 ... Air chamber

Claims (2)

Suction conveying means for sucking and conveying printing paper;
An inkjet head that is provided above the suction conveyance unit and that ejects a plurality of lines of ink arranged in a line in a direction orthogonal to the conveyance direction of the printing paper by the suction conveyance unit;
A sheet pressing unit provided above the suction conveyance unit and on the upstream side in the conveyance direction of the printing sheet with respect to each of the inkjet heads;
The suction conveying means includes
A first through-hole penetrating up and down, and a surface around the first through-hole and on the surface on the ink jet head side from the position of the first through-hole downstream in the conveyance direction of the printing paper A platen section having an air chamber that is opened to a position directly below the sheet pressing means at
A second through-hole penetrating vertically, and a belt moving in the transport direction on the platen portion;
Suction that is provided below the platen portion and sucks print paper onto the belt by sucking air above the belt through the first through hole, the air chamber, and the second through hole. With fans,
An ink jet printing apparatus comprising: The platen portion is
A plurality of the first through holes and a plurality of the air chambers corresponding to the periphery of each of the plurality of first through holes;
The inkjet printing apparatus according to claim 1, wherein the plurality of air chambers have substantially the same opening area.

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